Partitioning of a communications network

ABSTRACT

This invention relates to the partitioning of a communications network. The idea of the invention is to divide the logical connections of a communication network into several partitions, each partition representing a certain type of transmission traffic, such as access or regional traffic. The partitioning is based on simple criteria: capacity of an endpoint of a logical connection, representing a node; distance between a pair of endpoints, and traffic category representing the stability of the traffic. By using the partitioning, it is possible to separate a certain type of traffic (a certain type of logical connections) from the whole traffic picture of the network.

FIELD OF THE INVENTION

This invention relates to the partitioning of a communications network.

BACKGROUND OF THE INVENTION

A network planning process involves several competing targets. Thenetwork should be compact and flexible to operate, and easy to expand.The network capacity and investments are planned to follow the expectedtransmission needs and the actual sales of transport services. Thereexist many alternative architectures to realize the network.

The first network investment of the operator must be reasonable in size,but big enough to ensure credibility and the near future growth of thenetwork. In other words, a certain minimum coverage of the network isneeded, and the growth of the network must be secured technically andeconomically at the same time.

Usually, these matters mean the need of building the network gradually,to add and modify network nodes and transmission lines. The changes inthe network nodes can be frequent, which means repetitive additions ofequipment, changes in the use of existing equipment, the increase ofcapacity, and adding more line interfaces. Usually, the changes alsomean changes in synchronization paths and in network managementchannels.

Problems arise when the required changes are not possible to do in theexisting nodes, or they can be done, but the existing resources are notused efficiently. For example, more capacity is needed in a node andthus new equipment must be added into the node, but there is no freespace inside the rack. Or the added transmission capacity is for lowcapacity access traffic, but the node is capable of handling highcapacity regional traffic, when the node is too big and expensive tohandle just access traffic. In other words, the changes and the existingequipment must match with each other. Frequent changes in the futureshould be taken into account. The traffic in the network can be high orlow capacity traffic, and dynamic or stable traffic in relation to thetime period. The objective of the invention is to alleviate theabove-mentioned drawbacks. This is achieved in a way described in theclaims.

SUMMARY OF THE INVENTION

The idea of the invention is to divide the logical connections of acommunication network into several partitions, each partitionrepresenting a certain type of transmission traffic, such as access orregional traffic. The partitioning is based on simple criteria: capacityof an endpoint of a logical connection, representing a node; distancebetween a pair of endpoints, and traffic category representing thestability of the traffic. By using the partitioning, it is possible toseparate a certain type of traffic (a certain type of logicalconnections) from the whole traffic picture of the network. Thepartition offers a useful way for the designer of the network to decidewhat equipment is placed in each node, taking into account the costs andfuture growth.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is described in more detail by means ofFIGS. 1-2 in the attached drawings where,

FIG. 1 illustrates different types of transmission traffic,

FIG. 2 illustrates the inventive method as a flow chart.

FIG. 3 illustrates a network planning system for partitioning acommunication network, in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates what different types of transmission traffic can befound in a communication network. The vertical axis shows the capacitydemand of the traffic, and the horizontal axis shows the need ofrerouting in a large physical area, i.e. the stability of the traffic.P1 represents large capacity traffic, such as optical trunk traffic.Usually the optical traffic between endpoints in the backbone trunks ofa communications network is stable, i.e. there is no need for reroutingtraffic in a large physical area in relation to a certain period. P2represents traffic in a regional level (such as a city area). Capacityneeds are not as high as P1 has, but the traffic is more dynamic. P3represents low capacity traffic, such as leased cellular network trafficfor small businesses. In this case the need for rerouting is very high.

The starting point for the whole network plan is all desired logicalconnections (traffic requirements) that specify the endpoints of thelogical connections, capacity of the endpoints, and the descriptivecategory (traffic type) of the logical connections (e.g. mobile phonetraffic, interswitch traffic, data, leased line). The goal of thepartition process is to divide the logical connections into separatepartitions. The criteria that define a good partition are:

1. Equipment capacity is efficiently used. Not too low to get a goodutilization percentage, and not too high to have some room for growth.The growth estimates are different for different types of traffic.

2. The length of routes are as short as possible. This is because longerroutes require more intermediate equipment and thus increase the cost.Long routes are also more likely to be broken by some accident.

3. It is useful to separate the traffic with a certain stability fromthe traffic with other stabilities.

Since the above criteria require that a detailed plan for thepartitioning is available, it is impossible to use those criteriadirectly in the partitioning process. Therefore the following simplercriteria must be used:

-   -   1. The capacity of the endpoints of a logical connection in a        single partition is between given limits.    -   2. The distances between pairs of endpoints in a single        partition are between given limits.    -   3. A single partition contain a specific category of logical        connections (traffic type). The category can be used to deduce        how likely it is that the endpoints of the connection are going        to change. E.g. traffic between PSTN switches in large cities is        very stable and high capacity while leased line traffic used        e.g. by a group of shops is likely to change.

Special software can do the partition for separating the desired trafficfrom the logical connections. The designer chooses the capacity anddistance limits, and the right category. By using the partition, it iseasier for the designer to plan the network, taking into accountdifferent traffic types, equipment costs, and future growth.

FIG. 2 illustrates the invention as a flow chart. The input informationis the logical connections of the network. The information contains alltraffic demands for all kinds of traffic types. The software offers apossibility to select limits (21) for finding certain logicalconnections from all the logical connections. The limits are based onthe above-mentioned simple criteria. After selecting the limits, thesoftware forms two partitions (22): the primary partition which containsthe logical connections inside the selected limits, i.e. the partitionwhich is desired to be formed first, and the secondary partition, whichis the rest of the logical connection outside the selected limits. Thesoftware shows (23) graphically the primary partition to the designer,who can decide if the primary partition is acceptable. If the designerwants to change the partition made, it can be repeated (24). If thedesigner is satisfied with the partition, a new partition from thesecondary partition can be formed (25). The same steps (21,22,23,24) aredone for the new partition: selecting limits, forming two partitions,showing the primary desired partition (the latest one) graphically, andchanging the partition, if needed. The partition of the secondarypartition can be repeated until all desired traffic types have beenseparated into the separate partitions. The last partition is the latestsecondary partition, which is shown graphically (26) finally. Theminimum number of partitions is two when the secondary partition isshown graphically after the primary partition is accepted. In this casenew partitions from the secondary partition (25) are not required.

FIG. 3 illustrates a network planning system for partitioning acommunication network, in accordance with an embodiment of the presentinvention. A describing unit 30 is configured to describe logicalconnections in a network in a domain comprising at least two dimensions,the first dimension being for describing capacity needs of endpoints ofthe logical connections, and the second dimension being for describingre-routing needs of the logical connections. A selecting unit 32 isconfigured to select a value range for each of the dimensions and asearching unit configured to search for logical connections which arewithin the selected value ranges in the domain. A forming unit 34 of thenetwork planning system is configured to form a primary partition fromthe logical connections within the selected value ranges, the primarypartition being useful for deciding what equipment to place in at leastone endpoint.

The network planning system also includes a first forming unit 38configured to form a secondary partition from logical connections whichfail to belong to the primary partition. A second forming unit 40 isconfigured to form a new partition from the secondary partition, whereinlogical connections not belonging to the new partition form a latestsecondary partition. A third forming unit 42 is configured to formanother new partition from the logical connections of the latestsecondary partition. A representing unit 44 in the network planningsystem is configured to represent the primary partition graphically. Achanging unit 46 is configured to change the primary partition and agraphical display unit 48 is configured to display the secondarypartition graphically.

After the partition process, the designer can route and equip thenetwork nodes separately in each partition. The partitions are connectedtogether for getting the whole picture of the network. The inventivesoftware and the method offer an effective way to take into accountdifferent requirements of network planning: future growth,cost-effectiveness, reliability matters, and so on. Thus, the presentinvention provides a network planning method and system for partitioninga communication network, which describe logical connections in a networkin a domain comprising at least two dimensions. The first dimensiondescribes a capacity of endpoints of said logical connections, and thesecond dimension describes re-routing needs of said logical connections.The network planning method and system select a value range for each ofthe dimensions and search for logical connections which are within theselected value ranges in the domain. The network planning method andsystem further form a primary partition from the logical connectionswithin the selected value ranges to enable routing and equipping atleast one network node in the primary partition.

Although, the invention is described in a way that three parameters(capacity, distance, and traffic type) are taken into account in thepartitioning, it is possible to use another number of parameters, suchas only two parameters: capacity and traffic type. Or it is possible touse more than three parameters for forming a desired multidimensionaldomain for the limits using in the partitioning. The invention is amethod that can be used in many implementations and network solutions,in the scope of the inventive idea.

1. A network planning method for partitioning a communication network,said method comprising: describing logical connections in a network in adomain comprising at least two dimensions, the first dimension being fordescribing capacity needs of endpoints of said logical connections, andthe second dimension being for describing re-routing needs of saidlogical connections; selecting a value range for each of the dimensions;searching for logical connections which are within the selected valueranges in the domain; forming a primary partition from the logicalconnections within the selected value ranges; using the primarypartition to decide what equipment is placed in at least one endpoint;and equipping said at least one endpoint.
 2. A method according to claim1, further comprising representing the primary partition graphically. 3.A method according to claim 1, further comprising forming a secondarypartition from logical connections which fail to belong to the primarypartition.
 4. A method according to claim 3, further comprising forminga new partition from the secondary partition, wherein logicalconnections not belonging to the new partition form a latest secondarypartition.
 5. A method according to claim 4, further comprisingrepeating the forming of a new partition from the logical connections ofthe latest secondary partition.
 6. A method according to claim 3,further comprising showing the secondary partition graphically.
 7. Amethod according to claim 1, further comprising changing the partitionmade.
 8. A method according to claim 1, wherein the describing of thelogical connections is performed wherein the domain comprises a thirddimension that describes the distance between endpoints of said logicalconnections.
 9. A network planning system for partitioning acommunication network, said system comprising: describing means fordescribing logical connections in a network in a domain comprising atleast two dimensions, the first dimension being for describing capacityneeds of endpoints of said logical connections, and the second dimensionbeing for describing re-routing needs of said logical connections;selecting means for selecting a value range for each of the dimensions;searching means for searching for logical connections which are withinthe selected value ranges in the domain; and forming means for forming aprimary partition from the logical connections within the selected valueranges, said primary partition to determine what equipment to place inat least one endpoint.
 10. A system according to claim 9, furthercomprising representing means for representing the primary partitiongraphically.
 11. A system according to claim 9, further comprising firstforming means for forming a secondary partition from logical connectionswhich fail to belong to the primary partition.
 12. A system according toclaim 11, further comprising second forming means for forming a newpartition from the secondary partition, wherein logical connections notbelonging to the new partition form a latest secondary partition.
 13. Asystem according to claim 12, further comprising third forming means forforming another new partition from the logical connections of the latestsecondary partition.
 14. A system according to claim 11, furthercomprising graphical display means for displaying the secondarypartition graphically.
 15. A system according to claim 9, furthercomprising changing means for changing the partition.
 16. A systemaccording to claim 9, wherein said describing means is configured todescribe logical connections in the network in a domain which comprisesa third dimension that describes the distance between end points of thelogical connections.
 17. A network planning system for partitioning acommunication network, said system comprising: a describing unitconfigured to describe logical connections in a network in a domaincomprising at least two dimensions, the first dimension being fordescribing a capacity needs of endpoints of said logical connections,and the second dimension being for describing re-routing needs of saidlogical connections; a selecting unit configured to select a value rangefor each of the dimensions; a searching unit configured to search forlogical connections which are within the selected value ranges in thedomain; and a forming unit configured to form a primary partition fromthe logical connections within the selected value ranges, said primarypartition to determine what equipment to place in at least one endpoint.18. A system according to claim 17, further comprising a representingunit configured to represent the primary partition graphically.
 19. Asystem according to claim 17, further comprising a first forming unitconfigured to form a secondary partition from logical connections whichfail to belong to the primary partition.
 20. A system according to claim19, further comprising a second forming unit configured to form a newpartition from the secondary partition, wherein logical connections notbelonging to the new partition form a latest secondary partition.
 21. Asystem according to claim 20, further comprising a third forming unitconfigured to form another new partition from the logical connections ofthe latest secondary partition.
 22. A system according to claim 17,further comprising a changing unit configured to change the partition.23. A system according to claim 19, further comprising a graphicaldisplay unit configured to display the secondary partition graphically.24. A system according to claim 17, wherein said describing unit isconfigured to describe the logical connections in the network in adomain which comprises a third dimension that describes the distancebetween end points of the logical connections.
 25. An apparatusconfigured to search for logical connections having first and seconddimensions which are within respective selected value ranges, said firstdimension being for describing a capacity needs of endpoints of saidlogical connections, and said second dimension being for describingre-routing needs of said logical connections, and form a primarypartition from the logical connections within the selected ranges, saidprimary partition to determine what equipment to place in at least oneendpoint.
 26. A computer program embodied on a computer-readable medium,the computer program being configured to control a processor to searchfor logical connections having first and second dimensions which arewithin respective selected value ranges, said first dimension being fordescribing a capacity needs of endpoints of said logical connections,and said second dimensions being for describing re-routing needs of saidlogical connections, and form a primary partition from the logicalconnections within the selected value ranges, said primary partitionused to determine what equipment to place in at least one endpoint.